LITERATUREThe relation of the liver to the metabolism of carbohydrates has attracted the attention of investigators since Minkowski (1886) demonstrated a decrease in blood sugar and an increase of excretion of lactic acid in the urine of hepatectomized geese. It is now recognized that in the normal resting organism some lactic acid passes from the muscles to the blood, and small amounts (7 to 18 mgm. each hour) appear in the urine. Much larger amounts of this substance appear in both blood and urine after exercise; the quantity is affected considerably by the degree of "oxygen debt." The liver undoubtedly removes a considerable part of this excess lactic acid from the circulation and stores it as glycogen. It has been shown (Schneider and Widmann) that the liver is capable of retaining considerable amounts of optically inactive lactic acid injected into the portal vein; the concentration of lactic acid of the hepatic venous blood is not increased, nor is its optical activity increased.From the foregoing, it is evident that the functional efficiency of the hepatic parenchyma must have a considerable effect on the value for lactic acid in the blood, and on the rate with which the accumulations of this substance are removed following exercise. As the recent experiments of Eggleton and Evans disclosed, the liver is not the only agent in removing lactic acid from the blood. The heart and brain take up this substance readily, and resting muscles absorb some of the lactic acid liberated by working muscles. Considerable amounts may also be lost in the perspiration.Muscular exercise is, of course, the factor most likely to produce an increase in lactic acid of the blood in the individual case. Other factors also elevate the value for lactic acid of the blood; among these may be mentioned cardiac decompensation with circulatory failure (Meakins and Long), anemia, anoxemia, prolonged vomiting, irradiation, ether narcosis (Ronzoni and coworkers), and administration of various sugars